Real-Time Impedance Detection of Intra-Articular Space in a Porcine Model Using a Monopolar Injection Needle

Rheumatoid arthritis and osteoarthritis can be treated through specific drug injection into the intra-articular space. Several failures during drug injection attempts with conventional fluoroscopy and ultrasonography in a small area of the intra-articular space have been reported. In this work we present an innovative impedance measurement-based method/algorithm for needle tip positioning to enhance image-guided intra-articular vaccination treatment. A novel algorithm for detecting the intra-articular space in the elbow and knee joints of a live porcine model is reported. An impedance measurement system was developed for biological tissue measurement. The electrical impedance in the intra-articular space was monitored and the needle tip was examined by ultrasonography. The contrast dye was vaccinated and checked using fluoroscopy to confirm that the dye was properly inoculated in the cavity. The electrical impedance was estimated for various needle inclusion profundity levels in saline solution, which were broadly used to evaluate the proposed device for in vivo examinations. Good efficiency was observed in the impedance-based measurements using a monopolar injection needle for intra-articular therapy. To enhance the needle tip positioning for intra-articular therapy, the intended impedance measurement device with a monopolar injection needle can be used as a complement to existing modalities.

Lock-in Amplifier-Based Impedance Detection of Tissue Type Using a Monopolar Injection Needle

For successful intra-articular injection therapy, it is essential to accurately position the tip of the injection needle into the target joint area while administering the drug into the affected tissue. In this study, we investigated the feasibility of a monopolar injection needle and lock-in amplifier (LIA)-based impedance measurement system for detecting the tissue type where the needle tip is located. After positioning the monopolar injection needle tip into the dermis, hypodermis, or muscle layer of pork tissue, the electrical impedance was measured in the frequency range of 10 Hz to 10 kHz. We observed a difference in the results based on the tissue type where the needle was positioned (p-value < 0.01). Therefore, the monopolar injection needle with electrical impedance measurement can be used to improve intra-articular injection therapy through non-destructive and real-time monitoring of the needle position in the tissues.

Electrical Characterization of Pork Tissue Measured by a Monopolar Injection Needle and Discrete Fourier Transform based Impedance Measurement

Ultrasonography or fluoroscopy-guided needle injection has been used for intra-articular injection therapy against adhesive capsulitis and joint diseases. To improve the image-guided intra-articular injection therapy, electrical impedance measurement based positioning of the needle tip in the target tissue can be applied. The feasibility of the discrimination for the tissue layer at which the disposable monopolar injection needle tip position was investigated using the discrete Fourier transform (DFT)-based impedance measurement system and the ultrasound imaging device. The electrical impedance spectra of the pork tissue measured in the frequency range of 200 Hz to 50 kHz were characterized by designed equivalent circuit modeling analysis. The normalized impedance data of the tissue layers (dermis, hypodermis, and muscle) were significantly different from each other (p-value < 0.001). The DFT-based impedance measurement system with a monopolar injection needle can be complementary to the image-guided intra-articular injection therapy.

TRANSFER OF ELECTRIC CHARGE THROUGH Al-Se95Te5Sm-Te STRUCTURE

It is established that current passing through Al-Se95Te5<Sm>-Te structures is carried out by monopolar injection mechanism at participation of traps for holes. It is shown that the doping by samarium strongly influences on the current flow mechanism in the investigated structure due to changes in the energy spectrum of the local states.The local level parameters (concentration and energy state) controlling the electric charge transfer are defined with the use of existing theories of injection currents.Â

Prolonged Storage of Electrons in Monos-Structures

ABSTRACTThe transient process of the accumulation of charge in the Silicon Nitride by applying a positive voltage pulse to MONOS structure is investigated with the help of the experimental and theoretical methods (monopolar injection of electrons). The mathematical model of charge carriers transport in an amorphous nitride thin films in MONOS structures at the high electric fields has been developed. The essential peculiarity of this modelis that the injected carriers from the contact are captured by a quasi - continuous spectrum of states that there are traps, having an exponential distribution of densityin the nitride band gap and by the monoenergetic positively charged deep centers. The positive traps are made by the negative correlation energy defects. These defects are formed by the weak quasi- hydrogenous bonds Si-H-Si the changes of ones in consequences of a migration of hydrogen stipulate for the degradation processes in the nitride. It is established that the quasi - distributed traps are answered for the prolonged relaxation of current in the external circuit when t≫Tg in which the exponent α of function J∼t-α is determined by the parameter of the energy distribution of traps and by the applied voltage on the structure that is in agreement with experimental results and corresponds to the dispersive transport of carriers.